As they say, you can carry the message but not the person. She has to want sobriety for herself, not much you can do in that regard. A member of a group I go to is a serial relapser, even after treatment, duis, etc. Everyone is there for her, but she has a hard time staying sober.
Be sure to keep your sobriety safe! That's one thing you can do, show her it can be done. Best to you!